Isolating switch having improved separable contact assembly

ABSTRACT

An isolating switch comprising spaced, cylindrical hollow conductors capable of carrying high electrical currents mounted within gas filled, sealed concentric cylindrical enclosures. The isolating switch when opened, has a large insulating gap for withstanding high voltages. The switch includes a bridging member which retracts inside of one of the associated hollow poles or conductors when the switch is open, and extends to bridge the gap between the two cylindrical poles when the switch is closed, thus, providing a continuous electrical path from one pole or conductor to the other. The bridging member is actuated by a suitable driving mechanism or means. The means for establishing an electrically conducting path between two conductors is independent from the means for establishing a mechanical connection between said conductors. The bridging member includes electrical contacts which are of the loop type, that is generally U-shaped conductors which may be secured to a movable, electrically conducting drum to engage the inner periphery of both of the associated conductors.

United States Patent Kuhn ISOLATING SWITCH HAVING IMPROVED SEPARABLE CONTACT ASSEMBLY [451 Sept. 26, 1972 Primary Examiner-H. 0. Jones Assistant Examiner-William J. Smith Attorney-A. T. Stratton and Clement L. McHale [57] ABSTRACT An isolating switch comprising spaced, cylindrical hollow conductors capable of carrying high electrical currents mounted within gas filled, sealed concentric cylindrical enclosures. The isolating switch when opened, has a large insulating gap for withstanding high voltages. The switch includes a bridging member which retracts inside of one of the associated hollow poles or conductors when the switch is open, and extends to bridge the gap between the two cylindrical poles when the switch is closed, thus, providing a continuous electrical path from one pole or conductor to the other. The bridging member is actuated by a suitable driving mechanism or means. The means for establishing an electrically conducting path between two conductors is independent from the means for establishing a mechanical connection between said conductors. The bridging member includes electrical contacts which are of the loop type, that is generally U-shaped conductors which may be secured to a movable, electrically conducting drum to engage the inner periphery of both of the associated conductors.

22 Claims, 5 Drawing Figures ISOLATING SWITCH HAVING IMPROVED SEPARABLE CONTACT ASSEMBLY CROSS REFERENCES TO RELATED APPLICATIONS Certain inventions related to the invention disclosed in the present application are disclosed and claimed in copending application Ser. No. 114,631 filed concurrently by John T. Wilson and Arthur B. Niemoller and assigned to the same assignee as the present application. THE SAME ASSIGNEE AD THE PRESENT AP- PLICATION.

BACKGROUND OF THE INVENTION This invention relates to electrical switches and it has particular relation to improved electrical contact assemblies for such switches.

In certain types of electrical apparatus such as isolating switches of the type disclosed in US. Pat. Nos. 3,348,001 and 3,356,798 which are assigned to the same assignee as the assignee of the present application, the movable contact means is such that it has the dual responsibility of establishing a mechanical or structural link or connection to axially spaced conductors and also carrying electrical current between the two conductors. As a result, certain problems arise in providing the mechanical or structural characteristics necessary for proper linking or connection between the spaced conductors and the electrical characteristics necessary for proper current conduction. To provide a switch apparatus which accomplishes both purposes as efficiently or effectively as possible, it would be desirable to operatively isolate these two functions, whereby the mechanical linking structure may be constructed or arranged independently of the problems or requirements associated with the electrical current conducting means and vice versa. Furthermore, it would be advantageous to have a switch structure of the type described which provides an electrical connection that becomes more effectively secured as the current through it increases.

SUMMARY OF THE INVENTION In accordance with the invention, a pair of generally hollow cylindrical or tubular conducting and supporting means is separated by an axial gap and is mounted within a gas containing chamber or housing substantially filled with a gas which acts as an insulating medium. One of the tubular electrically conducting supporting means is adapted to house a movable bridging means. This bridging means when actuated from within the associated conductor toward the other electrically conducting supporting means provides an electrical connection between the two cylindrical supporting means when fully extended. The other supporting means has a receiving element or member having a center hole or opening, more specifically a disc-shaped receiving element having an outer diameter generally equal to the inner diameter of the cylindrical supporting means in which it is mounted. The center hole acts as a receptacle or guide for the bridging means previously described.

Generally, the bridging means is mounted on a drive shaft, one end of which is adapted to project into the center hole of the receiving or guiding means. The

other end of the driving shaft is operatively connected to a suitable driving means, such as a rack and pinion gear assembly or a gas driven piston. The movable bridging means includes a plurality of U-shaped electrically conducting'elements or loops disposed to surround it in a generally symmetrical pattern. There is a plurality of these conducting elements or members disposed on each end of the briding means. The inner section or portion of each of these U-shaped conducting means is attached to a movable electrically conducting drum and the outer portion is flexible. The inner portion of each conducting means is further anchored or secured by electrically insulated mounting studs placed between the drum and the inner portion of each conducting means or structure. As the telescoping bridging means is moved or actuated into its final closed position, the outer portion of the conducting means or structure engages the inner periphery of each of the associated hollow conductors, depressing or deflecting inwardly slightly to establish final engagement between the parts. When relatively high currents pass through the U-shaped conducting means, the directions of current which flows in both legs of each conducting means or structure are opposite because of the U-shape. This causes the flexible outer portion or leg to tend to move away from the rigidly mounted inner portion, thus compressing the outer portion against the inner periphery of the hollow conducting pole.

BRIEF DESCRIPTION OF THE DRAWINGS disconnect switch;

FIG. 1A shows a magnified or enlarged view of that portion of the disconnect switch where electrical contact between the movable bridging means and one of the associated conductors is established;

FIG. 1B shows a magnified view of the U-shaped contact in an undeflected operating state;

FIG. 2 shows an alternate actuating means for the bridging member, more specifically, a fluid driven piston;

FIG. 3 shows a partial sectional view, taken across line III -III in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and FIG. 1 in particular, a disconnect switch 10 embodying the invention is shown. Switch 10 comprises an outer shell or housing 11 which acts as a containment vessel for an electrically insulating gas, such as compressed air or sulfur hexafluoride (SF This outer shell or containment vessel 11 is attached or connected to the containment vessels or housing sections 12 and 14 on the right and left ends of containment vessel 10, respectively. Outer shells or containment pipes 12 and 14, act as the gas confining members of the electrical circuit or enclosed bus structure which is to be connected or interrupted by switch 10. Right bus duct section 12 comprises a containment vessel or housing 13 similar to containment vessel or housing 11 and left bus duct section 14 comprises a containment vessel or housing 15 also similar to containment vessel 11. Containment vessel 11 is joined to containment vessel 13 at flanges l6 and 18 on the adjacent ends of the respective containment vessles. Similarly, containment vessel 15 is attached to containment vessel 11 at flanges 10 and 22, respectively. It is contemplated that flanges l6 and 18 may be attached by means of a bolting arrangement and sealing gasket so that the switch can easily be disassembled from circuit section 12 and that the joint between flanges 20 and 22 may be similarly arranged. Mounted within containment vessel or pipe 1 l is a relatively stationary of fixed supporting means and electrical conductor 24. The combination supporting means and electrical conductor 24 may be a tubular or hollow cylindrical metallic pipe suitable for or capable of carrying large electrical currents. correspondingly, a metallic pipe or conductor 26 of substantially the same diameter or size as pipe 24 is contained or disposed within bus section 14.

The conductor 26 may be joined to first fixed supporting means or electrical conductor 24 by welding or any other suitable means at joint 28 to form a complete electrical connection or joint between conductor 24 and pipe or conductor 26. Similarly, an electrical conductor or second fixed supporting means 30 is mounted on the right side of switch 10. Conductor 30 may be welded or otherwise joined to a corresponding electrically conducting cylinder or pipe 32 at joint 34 similarly to the means used in connecting conductor 24 to conductor section 26. The electrical conductor or supporting means 24 may be supported, in turn, within containment vessel or gas container 11 by means of an insulated support 36, such as disclosed in-detail by A. B. Niemoller in US Pat. No. 3,351,705 which is assigned to the same assignee as the assignee of the present invention. Second supporting means or electrical conductor30 is similarly supported by supporting member 38 as described in the patent previously. As shown in FIG. 1, insulating support 38 is secured to electrical conductor section 30 in vicinity of region 40. Second fixed supporting means or electrical conductor 30 has an outer surface 4l and an inner surface'42. First supporting means or electrical conductor 24 has similar surfaces, specifically, outer surface 43 and inner surface 44. Inner surface 42 may have a diameter 42d substantially equal to the diameter 44d of inner surface 44 and outer surface 41 may have a diameter 41d substantially equal to the diameter 43d of outer surface 43. Attached to inner surface 42 in the vicinity of the insulating supporting means or insulator 38 is a third fixed supporting means 46. Supporting means 46 is generally a disc-shaped, reinforced metallic member rigidly attached or secured to inner wall 42 of electrical conductor 30 by suitable means, such as welding. The supporting means 46 is generally a solid structure with a central opening 47. Attached to the inner wall 44 of electrical conductor 24 is a receiving and guiding means or structure 48,. Receiving means 48 may be a solid, discshaped structure, similar to the supporting means 46, with a central recess or hole 60 which may be symmetrical about a common center line or longitudinal axis 49CL of the electrical conductors 24, 30 and 32. Hole 60 may be generally circular.

Also shown in FIG. 1 is the movable supporting or bridging means or switching segment 50. Switching segment 50 includes main body 52 having first and second ends 52L and 52R, respectively. Main body 52 forms part of the drive shaft 53 for moving or actuating the switch 10 between the closed and opened operating conditions. The additional parts or sections of the movable supporting or bridging means 50 also constitute or form part of the drive shaft 53, and are substantially symmetrical about the longitudinal axis 49C]... On the left, is guiding means 54 having a truncated conical seating section 56. Seating section 56 has a truncated conical shape which is complementary to a countersunk portion 58 of the opening 49 in receiving means 48. Cylindrical wall 60surrounds the remaining part of hole or recess 49 and also functions as a relatively friction free support or bearing surface for movable guide 54. The final portion of movable bridging section 50 is a cylindrically shaped guiding rod 62 which is disposed to the right of main body 52 as shown in FIG. 1. It is to be understood that main body or section 52 need not be cylindrical and may have a square cross section in a particular application. The cylindrically shaped rod 62 which constitutes part of drive shaft 53 is supported by and allowed to move freely through third supporting means. 46 by way of the central hole or opening 47. The entire bridgingmember or movable supporting-means 50 including main body 52, guiding means 54 and cylindrical shaft 62 is capable of moving longitudinally or axially in directions or 72. The actuating power for such motion may be. provided externally of switch 10 by a motor or similar driving means 63. As illustrated, motor 63 when energized rotates to cause shaft 64 to rotate. Shaft 64may have an electrically insulating section 66 which is adapted to withstand any high potential which is applied between the outer casing or gas enclosing means 1 l and current carrying metallic conductor 30. The rotary motion provided by motor 63 may be converted to transverse motion by rack and pinion gear mechanism 68. Consequently, drive shaft 53 may be moved or actuated in directions 70 or 72 to open or close switch 50, respectively.

Attached to main body 52 of switch 50 on drive shaft 53 is a radially extending supporting means 74 which may comprise a solid disc-shaped member 75 rigidly secured to main body 52 in the vicinity of end 52R and a similar supporting means 76 secured to main body 52 in the vicinity of end 52L. Disposed between discshaped radially extending members 75 and 76 is a cylindrical metallic conductor 78 which may be rigidly secured to members 75 and 76, and which may be disposed about a central axis common to central axis 49CL. Attached to conducting member or brace member 78 are insulated supports radially disposed and spaced symmetrically about conducting member 78 adjacent to both ends of the conducting member 78. Those supports near the end 52L are designated 80, while those supports near the end 52R are designated 82. Attached to each support 80 is U-shaped metallic electrical conductor 84F which is bent along one leg of the U-shaped conductor 84F to form a bracing section or lip portion 86. Bracing section 86 is rigidly attached to the supporting disk 76 in the vicinity of surface 87. Attached to the other leg of each U-shaped flexible metallic conductor 84F is a generally curved conducting segment 88. Each of the U-shaped flexible conducting sections 84F is disposed with the closed end of each of the U-shaped section 84F pointing in the direction of travel 72. Similarly, U-shaped flexible conducting sections 84R are mounted and oriented on the supports 82 in the opposite direction so that the closed ends of the sections 84R point in direction 72. Flexible, U-shaped metallic conductor 84R has a similar lip 86 which is disposed perpendicular to the shaft 53 and attached to radially extending disc-shaped support 75 and a curved conducting segment 88. Attached to the open end of the first electrical conductor 24 is a ring-shaped conductor 90F which is rigidly attached to the inner surface 44 of first supporting means 24. Similarly, a ringshaped conducting segment 90R is attached to inner surface 42 of second supporting and conducting means 30. Upon engagement, conducting section or ring 90F makes electrical contact with segments 88 on flexible conducting means 84F and segment or ring 90R makes electrical contact with segments 88 of flexible conducting means 84R.

Referring now to FIG. 1A, an enlarged view of the contact between movable contact segments 88 and the associated contact rings 90R or 90F is shown for the contact ring 90R. It will be noted that each of conductors 90R or 90F has a cross section which includes a varying diameter portion such that the diameter or effective thickness nearer to the area of initial contact is relatively larger than any diameter of said portion further away from said area of initial contact. This arrangement causes the curved segments 88 to move or flex inwardly as bridging member 50 is seated fully against stopping block 92 of guiding means 48 as shown in FIG. 1. This compresses each U-shaped segment 84F and 84R. The outer diameter of the rings 90R or 90F is indicated at 90WD whereas the inner diameter is indicated at 90ND.

FIG. 1B shows one of the U-shaped at least partially flexible, electrically conducting contacting segments or means 84 in its relaxed or undeflected operating position, whereas U-shaped, contacting segments 84F and 84R, as shown in FIG. 1, are in their compressed operating positions. It should be noted that the U- shaped conductors 84F and 84R have a spring-like or resilient property such that when they are in contact or engage rings 90F or 90R, the U-shaped conductors 84F and 84R are compressed causing force or pressure to be exerted which biases the ring-shaped segments 88 into engagement with the stationary ring-shaped conductors 90F or 90R. This arrangement provides or insures an electrically conducting path between electrical conductor section 24 and electrical conductor 30. When bridging member 50 is fully closed, as shown in FIG. 1, electrical current may flow through an electrical path which extends from electrical conductor or first fixed supporting means 24 through the contacts or ring segments 90F to the ring segments 88, which may both be formed from a silver-nickel material, through breaker jaws or U-shaped flexible conductor means 84F which may be formed from a cadmium-copper material, into radial supporting means 74 where it first flows through front supporting disk 76 and then through brace or cylindrical conductor 78 into rear supporting disk 75, which may each be formed from aluminum, to contact jaws 84R disposed on support 74 which may be formed from cadmium copper material. Current then flows from jaws 84R into contacts 88 and then into contact ring R which may also be formed from silver-nickel material to conductor or second fixed supporting means 30 which may be formed from aluminum.

Referring again to FIG. 13, it will be noted that U- shaped flexible conducting means 84 has an outer leg 84T and a inner leg 848. As current travels from contact 88 towards radial supporting disk 76, through the break jaws 84, the magnetic forces due to the opposing current directions 83F and 83R in legs 84B and 84T, respectively, tend to force legs 84T and 84B apart. The greater the current flow, the greater the forces tending to push the two legs apart. This arrangement, of course, has the effect of actuating the break jaws 884F and 84R into engagement with both the front and rear rigidly mounted rings 90F and 90R with greater pressure as higher currents flow through the conductors 24 and 30. Consequently, the bridging member 50 will remain in contact or engagement with the conductors 24 and 30 even during relatively high overload situations.

Similarly to the overall arrangement described in copending application Ser. No. 114,631 previously mentioned, the movable swtiching or bridging section 50 can be disengaged from the associated conductors ,24 and 30 and telescoped back into the hollow cylinder or conductor 30 by actuating the drive shaft 53 axially toward the right as viewed in FIG. 1. When the switch 10 is completely opened, bridging member; 50 is disposed or stored within cylinder 30 to provide a gap between conducting rings 90F and 90R to thereby insulate the conductors 24 and 30 from one another when a high voltage is present therebetween. To close switch 10, motor 63 may be energized to rotate in the proper direction. This rotary motion is transmitted through insulated shaft 64 to rack and pinion mechanism 68 where transverse longitudinal or axial motion is imparted to shaft 53 in axial direction 70. As the truncated conical leading or seating portion of guiding means or fustrum 54 approaches the complementary countersunk conic recess in receiving means 48, a mechanical connection but not necessarily an electrical contact may be established between first fixed supporting means or conductor 24 and second fixed supporting means or conductor 30. As shaft 53 is actuated further in direction 70, the left edges of the curved conductor segments 88 engage the fixed contact rings 90F and 90R which are rigidly attached or secured to cylindrical conductors 24 and 30, repsectively. The initial engagement of the conductor segments 88 is made adjacent to outer diameters 90WD or rings 90F and 90R. It is to be noted that a structural connection between the conductors 24 and 30 may occur simultaneously with electrical contact between segments 88 and the respective rigidly attached rings 90F and 90R or such a connection may occur after guiding means 54 and receiving means 48 are fully engaged. In anyevent, as motion of the shaft 53 continues in direction 70, the U-shaped break jaws 84F and 84R are compressed as the effective inner diameter of the contact ring 90F and 90R decreases. Finally, stopping block 92 contacts or engages area or region 94 on recieving means 48 to prevent further axial motion of switch segment 50. At

7 this point in the closing operation, shaft 53 is supported by both receiving means 48 and third supporting means 46, and an electrically conducting path has been established between electrical conductor 24 and electrical conductor 30.

' By reversing the direction of motor 23, the drive shaft 53 will be moved or actuated in direction 72, thus, reversing the closing operation previously described and disengaging the bridging member to open the switch 10.

Referring now to FIG. 3, a partial sectional view shown along line Ill-III of FIG. 1 is shown. It will be noted that the studs 80 and U-shaped break jaws 84F are circumferentially spaced around the radial supporting means 74 at substantially equally spaced angular intervals.

Referring now to FIG.- 2, an alternate driving means for shaft 53 is shown. This driving means is of the type disclosed in US. Pat. No. 3,346,789 by J. P. McKinnon and assigned to the same assignee as the assignee of the present invention. In this case, the rack and pinion gear 68 shown in FIG. 1, is replaced by a fluid driven piston mechanism 68A. An external source of fluid pressure not shown) applies a fluid 103 under pressure through pipe 98 into the volume between one side 104 of piston 106 and the cylinder walls 96 causing piston 106 to move in direction 70 and forcing rigidly attached shaft 53 to move accordingly. Motion will continue until the stopping block or member 92 in FIG. 1 makes contact with or engages the stopping surface or area 94. Disengagement of bridging member 50 can be actuated by supplying a similar fluid 102 to pipe 100, and into the volume between the other side 109 of piston 106 and the casing 96, causing the piston to move axially in direction 72 and the shaft 53 to move correspondingly until the surface 104 of piston 106 is stopped by lip or stop surface 107 which may be provided on the inner surface 96 of pressure container or cylinder 68P.

It is to be understood that the number of jaws 84F or 84R which are disposed on support member 74 may be varied as required to conduct current between current carrying conductor 24 and current carrying conductor 30. It shouldbe also understood that in addition to the rack and pinion driving mechanism or fluid driving mechanism shown in FIGS. 1 and 2, respectively, any other suitable means for moving actuating shaft 53 in both axial directions 70 or 72 may be used. It should also be understood that although certain metals or alloys have been indicated as suitable for certain parts of bridging member 50, other metals or alloys may be used where desired if they have the necessary proper structural, electrical and flexibility characteristics. It should also be noted that the gas insulating means in containment vessel 11 may be any suitable insulating gas, such as sulfer-hexafluoride. It should be understood that guiding means 54 may have any suitable seating means 56 including shapes other than those shown in FIG. 1 such as a rounded complete conic or parabolic shaped protrusion. It should be understood that any of the supporting means or conductorsmay be of any desired shape or size suitable to accomplish the purpose described. For example, it should also be understood that conductor 26 need not be of the same diameter as conductor 24. Finally, it should be understood that any suitable means for connecting segment 10 with segments 12 and 14 may be employed and it is not limited to bolting or welding.

The apparatus embodying the teaching of this invention has several important advantages. For example, it allows a structural connection to be established between the receiving means 48 and the guiding means 54 of bridging member 50 and at the same time independently allows for electrical current to flow through a current carrying path which is specifically designed to carry current and not to mechanically support the bridging member. Second, the bridging member is capable of telescoping within one of the cylindrical current carrying supports to conserve space within the gas enclosed switch. Third, use of the U-shaped contacting jaws results in increased pressure to be applied between the engaging parts as current increases, thus insuring that the bridging member will not disengage at a critical time such as when the overall switch structure is called upon to carry very high surge currents. In addition, window 1 10 may be provided for observing the opening and closing of switch section 50.

I claim as my invention:

1. An electric switch comprising a housing, a pair of spaced, generally fixed, electrically conducting supporting means disposed in said housing, each of said supporting means having connected thereto an electrically conducting contacting means, an electrically conducting movable bridging means, said bridging means having disposed adjacent to the opposite ends thereof a pair of spaced, partially flexible, electrically conducting contacting means, said movable bridging means being actuable to an operating position from a position of complete disengagement of both said flexible contacting means to cause said pair of flexible contacting means to generally simultaneously engage said contacting means on said pair of fixed supporting means and to exert pressure between said flexible contacting means and said fixed contacting means due to said flexibility of said flexible conducting means so as to provide an electrically conducting path between said fixed contacting means on said pair of supporting means.

I 2. An electric switch as claimed in claim 1 wherein at least one of said fixed supporting means is generally tubular and opened at one end.

3. An electric switch as claimed in claim 2 wherein said movable bridging means is movable substantially into one end of said tubular supporting means.

4. An electric switch as claimed in claim 3 wherein both of said pair of fixed supporting means are generally tubular.

5. An electric switch as claimedin claim 4 wherein said pair of fixed supporting means is disposed along a common axis.

6. An electric switch as claimed in claim 5 wherein said fixed supporting means have substantially equal diameters and, are disposed with an open end of each supporting means being disposed in a face to face relationship with an open end of the other supporting means.

7. An electric switch as claimed in claim 6 wherein said movable bridging means includes a guiding means and at least one of said fixed supporting means includes a receiving means adapted to engage said guiding means.

8. An electric switch as claimed in claim 7 wherein at least one of said fixed supporting means includes an additional supporting means for supporting said movable bridging means.

9. An electric switch as claimed in claim 8 wherein each of said pair of fixed supporting means comprises a wall portion having an inner and outer surface and having an inner and outer diameter respectively, said receiving means being disposed within said first fixed supporting means and secured to said inner surface of said wall portion, said additional supporting means being disposed within said second fixed supporting means and secured to said inner surface of said wall.

10. An electric switch as claimed in claim 9 wherein said receiving means and said supporting means each comprise disc-shaped solid members having a predetermined outer diameter, said predetermined diameter being substantially equal to said inner diameter of said wall portion of each of said fixed supporting means, said additional supporting means having a central opening and said receiving means having a recess disposed away from the outer periphery of said receiving means.

11. An electric switch as claimed in claim 10 wherein said recess is a central recess which is symmetrically disposed with respect to said axis.

12. An electric switch as claimed in claim 11 wherein said central recess comprises a hole extending through said disc-shaped solid member of said receiving means.

13. An electric switch as claimed in claim 12 wherein said hole is generally circular in shape, said guiding means having a shape which is complementary to the shape of said hole and generally symmetrical about said axis, said central opening in said additional supporting member being generally cylindrical in shape and generally symmetrical about said axis, said movable supporting means comprising a main body, a cylindrically shaped rod, said guiding means being secured to one end of said main body, said one end being disposed closer to said receiving means, said cylindrically shaped rod being secured to the other end of said main body, said rod and said main body being disposed about a common central axis, said central opening in said additional supporting means being adapted to permit said rod to move through it along said common central axis.

14; An electric switch as claimed in claim 9 wherein each of said electrically conducting contacting means comprise generally ring-shaped metallic electrical conductors having an inner and an outer diameter and corresponding inner and outer peripheral surfaces, said outer diameter of each of said ring-shaped conductors generally being substantially equal to said inner diameter of said first and second fixed supporting means, one said ring-shaped metallic electrical conductors being secured to said inner surface of said first fixed supporting means and being closer to the open end of said first fixed supporting means to which said receiving means is secured, said second ring-shaped metallic electrical conductor being secured to said inner surface of said second fixed supporting means and being closer to the open end of said second fixed supporting means than said additional supporting means.

- 15. An electric switch as claimed in claim 14 wherein said inner surface of each of said first and second ringshaped metallic electrical conductors is generally arcuate with a relatively larger inner diameter at one end thereof and a relatively smaller inner diameter at the other end thereof, both rings being oriented on their respective first and second supporting means with the longitudinal direction of travel of said movable bridging means being from said one end toward said other end of each ring-shaped electrical conductor.

16. An electric switch comprising a housing, first and second spaced, generally fixed, generally tubular, electrically conducting supporting means, each having a wall portion with inner and outer surfaces having corresponding inner and outer diameters respectively,.

being open at one end thereof, said supporting means being disposed along a common axis in an open end to open end relationship within said housing, each of said supporting means having connected thereto an electrically conducting contacting means, said first supporting means having therein a receiving means secured to said inner surface and adapted to receive a guiding means disposed on a movable bridging means, said second supporting means having therein an additional supporting means secured to said inner surface and adapted to support a movable bridging means, said electrically conducting, contacting means comprising generally ring-shaped metallic electrical conductors each said latter mentioned electrical conductor having an inner and an outer diameter and corresponding inner and outer peripheral surfaces, said outer diameter of each of said ring-shaped conductors generally being substantially equal to said inner diameter of said fixed supporting means, one said ring shaped metallic electrical conductor being secured to said inner surface of said first fixed supporting means and being disposed thereon closer to the open end of said first fixed supporting means, said second ring-shaped metallic electrical conductor being secured to said inner surface of said second fixed supporting means and being closer to the open end of said second fixed supporting means said additional supporting means, said inner surface of each of said first and second ring-shaped metallic electrical conductors being generally arcuate having a relatively larger inner diameter at one end thereof and a relatively smaller inner diameter at the other end thereof, a movable bridging means movable substantially into said open ends of said tubular supporting means, said bridging means having disposed adjacent to the opposite ends thereof spaced, partially flexible, electrically conducting contacting means, said bridging means also having thereon a guiding means, both said previously mentioned ring shaped conductors being disposed on said respective first and second supporting means with the longitudinal direction of travel of said movable bridging means being from said larger diameter toward said smaller diameter of each said ringshaped electrical conductors, said movable bridging means being actuable to an operating position to cause said pair of flexible conducting means to generally concurrently separately engage said contacts on said pair of fixed supporting means and to exert pressure between said flexible conducting means and said fixed ring shaped contacting means due to said flexibility of said flexible contact conducting means so as to provide an electrically conducting path between said fixed ring shaped contacting means on said pair of supporting means, said partially flexible electrically conducting contacting means comprising at least one generally U- shaped metallic contacting elementdisposed longitudinally on said movable bridging means, said U-shaped metallic contacting elements having inner and outer legs disposed generally parallel to said bridging means for providing said flexibility.

17. An electric switch as claimed in claim 23 wherein each of said flexible contacting means includes a plurality of U-shaped metallic elements each secured at said inner leg to said movable bridging means, said elements being mounted generally symmetrically about said longitudinal axis.

18. An electric switch as claimed in claim 17 wherein said movable bridging means comprises a main body including a pair of spaced, radially extending supporting means, each of said flexible contacting means being attached to one of said radially extending supporting means.

19. An electric switch as claimed in claim 18 wherein said main body includes a drive shaft, said radially extending supporting means being mounted on said drive shaft.

20. An electric switch as claimed in claim 19 wherein said radially extending supporting means comprises a pair of disks each having a central hole adapted to receive said drive shaft, each of said discs having attached thereto and electrically connected thereto said plurality of said U-shaped metallic elements, said U- shaped metallic elements of each flexible contacting means having open ends andclosed ends with the open ends of said U-shaped metallic elements of each of said contacting means being mounted on the associated disk with the open ends disposed adjacent the associated disk and open in a direction opposite to the direction which the open ends of the U-shaped metallic elements of the other contacting means mounted on the other of said disks are open.

21. An electric switch as claimed in claim 20 wherein said main body includes a cylindrical brace member capable of conducting electrical current, said brace member being disposed between and connecting said disks, and a plurality of electrical insulators, each of said insulators being attached at one end of said brace member and at the other end to one of said U-shaped metallic elements.

22. An electric switch as claimed in claim 21 wherein each of said U-shaped metallic elements includes a lip portion, said lip portions of the respective flexible contacting means being disposed to engage said first and second rings at said larger outer diameter of each of said ring-shaped conductors upon movement of said movable bridging means toward said receiving means, further longitudinal movement of said movable briding means causing said flexible outer leg of each of said U- shaped metallic elements to flex inwardly toward said bridging means as said lip portions move toward the smaller inner diameters of said first and second ringshaped conductors, the flexing of said contacting means resulting in increased contact pressure between each of said flexible contacting means and the respective ring-shaped conductors, said inner, leg of each U- shaped metallic element having an inner lip portion bent generally perpendicular to said inner leg of said U- shaped metallic element, said inner lip portion being secured and elegtrically connected to one end surface of the associate disc to thereby provide a current carrying path from said first fixed supporting means through one of said ring-shaped conductors, one of said contacting means, one of said discs, said brace member, the other of said discs, the other of said flexible contacting means, the other of said ring-shaped conductors, to said second fixed supporting means when said switch is closed. 

1. An electric switch comprising a housing, a pair of spaced, generally fixed, electrically conducting supporting means disposed in said housing, each of said supporting means having connected thereto an electrically conducting contacting means, an electrically conducting movable bridging means, said bridging means having disposed adjacent to the opposite ends thereof a pair of spaced, partially flexible, electrically conducting contacting means, said movable bridging means being actuable to an operating position from a position of complete disengagement of both said flexible contacting means to cause said pair of flexible contacting means to generally simultaneously engage said contacting means on said pair of fixed supporting means and to exert pressure between said flexible contacting means and said fixed contacting means due to said flexibility of said flexible conducting means so as to provide an electrically conducting path between said fixed contacting means on said pair of supporting means.
 2. An electric switch as claimed in claim 1 wherein at least one of said fixed supporting means is generally tubular and opened at one end.
 3. An electric switch as claimed in claim 2 wherein said movable bridging means is movable substantially into one end of said tubular supporting means.
 4. An electric switch as claimed in claim 3 wherein both of said pair of fixed supporting means are generally tubular.
 5. An electric switch as claimed in claim 4 wherein said pair of fixed supporting means is disposed along a common axis.
 6. An electric switch as claimed in claim 5 wherein said fixed supporting means have substantially equal diameters and, are disposed with an open end of each supporting means being disposed in a face to face relationship with an open end of the other supporting means.
 7. An electric switch as claimed in claim 6 wherein said movable bridging means includes a guiding means and at least one of said fixed supporting means includes a receiving means adapted to engage said guiding means.
 8. An electric switch as claimed in claim 7 wherein at least one of said fixed supporting means includes an additional supporting means for supporting said movable bridging means.
 9. An electric switch as claimed in claim 8 wherein each of said pair of fixed supporting means comprises a wall portion having an inner and outer surface and having an inner and outer diameter respectively, said receiving means being disposed within said first fixed supporting means and secured to said inner surface of said wall portion, said additional supporting means being disposed within said second fixed supporting means and secured to said inner surface of said wall.
 10. An electric switch as claimed in claim 9 wherein said receiving means and said supporting means each comprise disc-shaped solid members having a predetermined outer diameter, said predetermined diameter being substantially equal to said inner diameter of said wall portion of each of said fixed supporting means, said additional supporting means having a central opening and said receiving means having a recess disposed away from the outer periphery of said receiving means.
 11. An electric switch as claimed in claim 10 wherein said recess is a central recess which is symmetrically disposed with respect to said axis.
 12. An electric switch as claimed in claim 11 wherein said central recess comprises a hole extending through said disc-shaped solid member of said receiving means.
 13. An electric switch as claimed in claim 12 wherein said hole is generally circular in shape, said guiding means having a shape which is complementary to the shape of said hole and generally symmetrical about said axis, said central opening in said additional supporting member being generally cylindrical in shape and generally symmetrical about said axis, said movable supporting means comprising a main body, a cylindrically shaped rod, said guiding means being secured to one end of said main body, said one end being disposed closer to said receiving means, said cylindrically shaped rod being secured to the other end of said main body, said rod and said main body being disposed about a common central axis, said central opening in said additional supporting means being adapted to permit said rod to move through it along said common central axis.
 14. An electric switch as claimed in claim 9 wherein each of said electrically conducting contacting means comprise generally ring-shaped metallic electrical conductors having an inner and an outer diameter and corresponding inner and outer peripheral surfaces, said outer diameter of each of said ring-shaped conductors generally being substantially equal to said inner diameter of said first and second fixed supporting means, one said ring-shaped metallic electrical conductors being secured to said inner surface of said first fixed supporting means and being closer to the open end of said first fixed supporting means to which said receiving means is secured, said second ring-shaped metallic electrical conductor being secured to said inner surface of said second fixed supporting means and being closer to the open end of said second fixed supporting means than said additional supporting means.
 15. An electric switch as claimed in claim 14 wherein said inner surface of each of said first and second ring-shaped metallic electrical conductors is generally arcuate with a relatively larger inner diameter at one end thereof and a relatively smaller inner diameter at the other end thereof, both rings being oriented on their respective first and second supporting means with the longitudinal direction of travel of said movable bridging means being from said one end toward said other end of each ring-shaped electrical conductor.
 16. An electric switch comprising a housing, first and second spaced, generally fixed, generally tubular, electricalLy conducting supporting means, each having a wall portion with inner and outer surfaces having corresponding inner and outer diameters respectively, being open at one end thereof, said supporting means being disposed along a common axis in an open end to open end relationship within said housing, each of said supporting means having connected thereto an electrically conducting contacting means, said first supporting means having therein a receiving means secured to said inner surface and adapted to receive a guiding means disposed on a movable bridging means, said second supporting means having therein an additional supporting means secured to said inner surface and adapted to support a movable bridging means, said electrically conducting, contacting means comprising generally ring-shaped metallic electrical conductors each said latter mentioned electrical conductor having an inner and an outer diameter and corresponding inner and outer peripheral surfaces, said outer diameter of each of said ring-shaped conductors generally being substantially equal to said inner diameter of said fixed supporting means, one said ring shaped metallic electrical conductor being secured to said inner surface of said first fixed supporting means and being disposed thereon closer to the open end of said first fixed supporting means, said second ring-shaped metallic electrical conductor being secured to said inner surface of said second fixed supporting means and being closer to the open end of said second fixed supporting means said additional supporting means, said inner surface of each of said first and second ring-shaped metallic electrical conductors being generally arcuate having a relatively larger inner diameter at one end thereof and a relatively smaller inner diameter at the other end thereof, a movable bridging means movable substantially into said open ends of said tubular supporting means, said bridging means having disposed adjacent to the opposite ends thereof spaced, partially flexible, electrically conducting contacting means, said bridging means also having thereon a guiding means, both said previously mentioned ring shaped conductors being disposed on said respective first and second supporting means with the longitudinal direction of travel of said movable bridging means being from said larger diameter toward said smaller diameter of each said ring-shaped electrical conductors, said movable bridging means being actuable to an operating position to cause said pair of flexible conducting means to generally concurrently separately engage said contacts on said pair of fixed supporting means and to exert pressure between said flexible conducting means and said fixed ring shaped contacting means due to said flexibility of said flexible contact conducting means so as to provide an electrically conducting path between said fixed ring shaped contacting means on said pair of supporting means, said partially flexible electrically conducting contacting means comprising at least one generally ''''U-shaped'''' metallic contacting element disposed longitudinally on said movable bridging means, said U-shaped metallic contacting elements having inner and outer legs disposed generally parallel to said bridging means for providing said flexibility.
 17. An electric switch as claimed in claim 23 wherein each of said flexible contacting means includes a plurality of U-shaped metallic elements each secured at said inner leg to said movable bridging means, said elements being mounted generally symmetrically about said longitudinal axis.
 18. An electric switch as claimed in claim 17 wherein said movable bridging means comprises a main body including a pair of spaced, radially extending supporting means, each of said flexible contacting means being attached to one of said radially extending supporting means.
 19. An electric switch as claimed in claim 18 wherein said main body includes a drive shaft, said radially extending supporting means being mounted on said drive shaft.
 20. An electric switcH as claimed in claim 19 wherein said radially extending supporting means comprises a pair of disks each having a central hole adapted to receive said drive shaft, each of said discs having attached thereto and electrically connected thereto said plurality of said U-shaped metallic elements, said U-shaped metallic elements of each flexible contacting means having open ends and closed ends with the open ends of said U-shaped metallic elements of each of said contacting means being mounted on the associated disk with the open ends disposed adjacent the associated disk and open in a direction opposite to the direction which the open ends of the U-shaped metallic elements of the other contacting means mounted on the other of said disks are open.
 21. An electric switch as claimed in claim 20 wherein said main body includes a cylindrical brace member capable of conducting electrical current, said brace member being disposed between and connecting said disks, and a plurality of electrical insulators, each of said insulators being attached at one end of said brace member and at the other end to one of said U-shaped metallic elements.
 22. An electric switch as claimed in claim 21 wherein each of said U-shaped metallic elements includes a lip portion, said lip portions of the respective flexible contacting means being disposed to engage said first and second rings at said larger outer diameter of each of said ring-shaped conductors upon movement of said movable bridging means toward said receiving means, further longitudinal movement of said movable briding means causing said flexible outer leg of each of said U-shaped metallic elements to flex inwardly toward said bridging means as said lip portions move toward the smaller inner diameters of said first and second ring-shaped conductors, the flexing of said contacting means resulting in increased contact pressure between each of said flexible contacting means and the respective ring-shaped conductors, said inner leg of each U-shaped metallic element having an inner lip portion bent generally perpendicular to said inner leg of said U-shaped metallic element, said inner lip portion being secured and electrically connected to one end surface of the associated disc to thereby provide a current carrying path from said first fixed supporting means through one of said ring-shaped conductors, one of said contacting means, one of said discs, said brace member, the other of said discs, the other of said flexible contacting means, the other of said ring-shaped conductors, to said second fixed supporting means when said switch is closed. 